1. Field of the Invention
The present invention relates to a laminated ceramic electronic component such as a laminated capacitor. In more detail, the present invention relates to a laminated ceramic electronic component using a ceramic sintered body having a principal component of CaZrO3 suitable for temperature compensation.
2. Description of the Related Art
Use of base metals such as Ni and Cu as inner electrodes have been attempted for reducing the production cost of laminated ceramic electronic components such as laminated capacitors. However, since these base metals are readily oxidized, laminated ceramic green sheets having inner electrodes as described above have required firing in a neutral or reducing atmosphere. Accordingly, ceramic materials capable of being fired under the neutral or reducing atmosphere, for example a ceramic mainly composed of BaTiO3, have been widely used for manufacturing such laminated ceramics.
Meanwhile, a variety of laminated capacitors for use in temperature compensation have been proposed as elements for use in temperature compensation. Ceramics to be used in the laminated capacitors for use in temperature compensation are required to have a small rate of temperature change of electrostatic capacitance. Accordingly, CaZrO3 based ceramics have been used as the ceramic materials constituting the laminated ceramic capacitor for use in temperature compensation.
The CaZrO3 based ceramics are suitable for the materials of the temperature compensation ceramics because their specific dielectric constant is low and they have a smaller rate of temperature change of electrostatic capacitance than BaTiO3 based ceramics.
However, the CaZrO3 based ceramics require a firing temperature as high as about 1400xc2x0 C. as compared with the lower firing temperature of the BaTiO3 based ceramics, making it difficult to fire in a neutral or reducing atmosphere, and therefore the CaZrO3 based ceramics have been usually fired in the air. As a result, expensive inner electrode materials such as Pd, which are hardly oxidized even by firing in the air, have been inevitably used for the CaZrO3 based ceramics. Consequently, it was difficult to reduce the manufacturing cost because a large amount of energy has been needed due to the high firing temperature, and the materials for the inner electrodes are expensive.
Accordingly, the object of the present invention is to provide a laminated ceramic electronic component using CaZrO3 based ceramics that can be fired in a neutral or reducing atmosphere, thereby allowing inner electrodes to be formed using cheap base metals such as Ni.
The present invention provides a laminated ceramic electronic component comprising: a ceramic sintered body having a principal component of CaZrO3 and containing a MnO2 phase and a glass phase; inner electrodes comprising a base metal disposed in the ceramic sintered body; and outer electrodes formed on the outer surface of the ceramic sintered body.
In the laminated ceramic electronic component according to the present invention, a ceramic sintered body having a principal component of CaZrO3 in which a MnO2 phase is formed is used. The MnO2 phase serves for stabilizing the ceramic sintered body when firing in a neutral or reducing atmosphere.
The ceramic sintered body containing the glass phase can be obtained by sintering at a temperature as low as 1250xc2x0 C. or less.
Accordingly, it is possible to use inner electrodes comprising a base metal, such as Ni and Cu, because the CaZrO3 based ceramics having a small rate of temperature change of electrostatic capacitance is obtained by firing at a relatively low temperature in a neutral or reducing atmosphere.
Preferably, the ceramic sintered body further comprises a TiO2 phase in the present invention.
Ni or Cu may be used for the base metal constituting the inner electrodes in the present invention.
The laminated ceramic electronic component comprising the ceramic sintered body mainly composed of the CaZrO3 based ceramics according to the present invention may be advantageously used for the laminated capacitor for use in temperature compensation.